一种适用于镍催化烯烃聚合及与极性单体共聚的约束结构对称策略

A Constrained Structural Symmetry Strategy for Nickel-Catalyzed Olefin Polymerization and Copolymerization with Polar Monomers

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DOI 10.1021/jacs.5c16150
刊名
年,卷(期) 2025, 147(49)
作者
作者单位 安徽大学

摘要
在α-二亚胺镍催化烯烃聚合反应中,传统性能提升策略主要集中于调控位阻效应与电子特性。虽然这些方法能有效抑制β-氢消除并提高分子量,但往往导致共聚反应中极性单体插入率降低。本文报道了一种通过设计氧杂大环α-二亚胺镍催化剂实现的受限结构对称性策略,该策略强制二苯甲基取代基在N-Ni-N平面同侧形成特定空间排列。相较于取代基位于异侧的双苄基模拟催化剂,这种拓扑受限催化剂展现出更高活性(>107 g·mol–1·h–1)、可制备更高分子量聚合物,并在共聚反应中实现更高极性单体插入率(达5.3 mol%)。这些发现揭示了结构对称性调控在打破分子量控制与极性共聚单体插入传统权衡关系中的独特作用,为设计高性能烯烃聚合催化剂提供了新范式。此外,环醚结构单元可作为锚定点,将催化剂固载于路易斯酸改性二氧化硅表面。这种多相化过程能进一步提升聚合物分子量、降低支化密度,并改善产物形貌可控性。
Abstract
Conventional strategies for enhancing performance in α-diimine nickel-catalyzed olefin polymerization have predominantly focused on modulating steric hindrance and electronic properties. While effective in suppressing β-hydride elimination and increasing molecular weight, these approaches often lead to reduced incorporation of polar monomers in copolymerization reactions. Herein, we report a constrained structural symmetry strategy through the design of an oxa-macrocyclic α-diimine nickel catalyst, which enforces a specific spatial arrangement of the dibenzhydryl substituents on the same side of the N–Ni–N plane. Compared with the simulant catalyst bearing dibenzyl bulky groups on the opposite side, the topologically constrained catalyst exhibits higher activity (>107 g·mol–1·h–1), produces polymer with a higher molecular weight, and also achieves enhanced polar monomer incorporation (up to 5.3 mol %) in copolymerization. These results underscore the unique role of structural symmetry manipulation in breaking the conventional trade-off between molecular weight control and polar comonomer incorporation, offering a new paradigm for designing high-performance olefin polymerization catalysts. Furthermore, the cyclic ether moiety can serve as an anchor to immobilize the catalyst on Lewis acid-modified silica. This heterogenization leads to increased polymer molecular weight, reduced branching density, and improved control over product morphology.
关键词
催化剂 共聚 烃类 单体 镍
KeyWord
Catalysts Copolymerization Hydrocarbons Monomers Nickel
基金项目
页码 45486-45494
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Qasim, M.; Ahmad, N.; Wang, F. Z.*; Tan, C.*; Chen, M.*. 一种适用于镍催化烯烃聚合及与极性单体共聚的约束结构对称策略 [J]. Journal of the American Chemical Society. 2025; 147; (49). 45486 - 45494.

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